Electric lamp.



1. B. SPEED. l

ELECTRIC LAMP. APPLlATIoN HLED FE8.23,1915.

1,200,040.- Patented oop. 3,1916.

l/l//nessesx /nvenfors I Me. James 5. Speed @@NQMM @mM/ffy sTATEs PATENT oEErcE.

JAMES BUCKNER SPEED, 0F WEST NEW BRIGHTON, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORA- TION OF NEW YORK.

ELECTRIC LAMP.

Specification of Letters Patent.

Patented oct. a, y1916.

Application led February 23, 1915. Serial N o. 9,866.

To all whom t may concern:

Be it known that I, JAMES B. SPEED, a citizen of the United States, residing at West New Brighton, in the county of Richmond and State of New York, have invented certain new and useful Improvements in Electric Lamps, of which the following is a full, clear, concise, and exact description.

vThis invention relates to electric lamps and more particularly to what are commonly called incandescent electric lamps.

The general object of the invention is to provide an incandescent electric lamp with luminous material, which for a considerable period of time after the lamp is extinguished will give off light which has been stored up in it while the lamp was burning. This luminous feature of the lamp enables it to be easily located in a dark room and so facilitates its use.

Luminous material has, of course, been applied to many objects such as -match boxes, clock faces, etc., for the purpose of rendering them easily visible in the dark. The present invention, however, involves something more than the` mere application of light storing material'to an object which itis desirous to render luminous.

According to the present invention, light storing material is so combined with the= structure of an incandescent lamp that said material receives and stores up light emanating from the light-giving element of the lamp. No attempt is made to'place the light storing material where it can receive light from any source outside thelarnp itself, the whole object being to so arrange said material that it will, while the lamp is burning, receive and store up light emanating therefrom, which light will gradually be given oflI after the lamp is extingulshed. More specifically considered, the invention resides in the placing of light storlng material within the hollow stem of an incandescent lamp. Vhen so located, the material is sealed into and becomes an inher ent part of the lamp structure, and 1s protected from deterioration by handling or atmospheric conditions. If the light storing material were located withln the evacuated chamber of the lamp, for example, by being applied in the form of paint to the inside of the bulb or the outside of the lamp stem or'filament support, it would probably injuriously affect the life or efficiency of the lamp; but by, placing said material within the hollow stem all such objections to its use are avoided.

My invention will be understood from the followlng description of certain preferred embodiments thereof, taken in connection with the drawings, in which- Figure 1 shows an incandescent electric lamp, partly in section, with a mixture of transparent material and light storing materlal within the stem; Fig. i tary view partly in section filled with powdered or granular light storing material; and Fig. 3 is a fragmentary 'v1ew, partly in section, showing a lamp stem containing luminous'material applied in a coating to its inside. v

Like parts are referred to by the same reference characters throughout the .various figures of the drawings.

For the purpose of illustration, the invention is shown embodiedin a well known form of tungsten incandescent electric lamp. The lamp base is shown at 5 as being of the Well-known threaded form adapted to screw into a socket. The evacuated container or bulb is indicated at 6. Sealed intoone end of the bulb 6 is a hollow stem 7 carrying the Afilament support 8 upon which the filament'9 is mounted. The leading-in wires which connect the terminals of the base 5 with the ends of the filament are shown at 10 sealed into and leading through the stem 7.

Any suitable kind of llight storing material may be employed in carrying out my invention, for example the well known sulfid of calcium prepared for making luminous paint, or the well known luminous suld of zinc.

In Fig. 1, the lamp stem 7 is shown as filled with a mixture of llight storing material in either powdered or granular formand broken glass or clear quartz. The function of the glass or quartz is to separate the particles of light storing material and permit the light emanating from the lamp filament to permeate the mass of light storing material 11, thereby increasing the effec-- l.rial such as luminous paint 13.

, therein,

What is claimed i's:

1. An electric lamp comprising an evacuated container, a hollow stem mounted a. filament support carried by said stem, a filament mounted on said support, and light storing material in said stem arranged to receive light emanating from said filament.

2. An electric lamp comprising an evacuated container, a hollow stem mounted therein, a filament support carriedby said stem, a filament mounted on said support, and a mixture'of transparent material and light storing material in said stem arranged to receive light emanating from said filament. i5 In Witness whereof, l hereunto subscribe my namethis 19th day of February, A. D. 1915.

JAMES BUCKNER SPEED.

1Witnesses:

K. L. STAHL, E. EDLER. 

